Calculate your estimated due date and track your pregnancy week by week.
Estimated delivery date from last period
This free calculator gives you instant, accurate results with no signup required. Use it to make smarter, more informed financial and life decisions.
Always double-check important financial decisions with a qualified professional. This calculator provides estimates for guidance purposes. Results may vary based on your specific circumstances.
Due date calculations based on your last menstrual period (LMP) assume a standard 28-day cycle with ovulation on day 14 — but only about 4-5% of babies actually arrive on their calculated due date. Most births happen within a 2-week window around it.
If your cycle is longer or shorter than 28 days, the standard calculation can be off by several days. This calculator adjusts for your actual average cycle length, which improves accuracy compared to basic due date estimators that assume everyone has identical cycles.
Early ultrasounds (typically performed between weeks 8-12) are generally considered more accurate than LMP-based calculations alone, since they measure the embryo directly rather than relying on cycle assumptions. If your dates differ between LMP calculation and ultrasound, doctors usually prioritize the ultrasound measurement.
Use the calculator above as a helpful planning estimate for tracking trimesters and milestones — but always treat your doctor's calculated due date, especially after an early ultrasound, as the more reliable reference point.